Trace gas (e.g., CO2 and methane) emissions from soils play a significant role in global climate change. Social, economic, and political forces are at work, which make it imperative that the scientific community provide quantitative measurement techniques and accurate data. Chambers are the most widely-used method for measuring trace gas emissions from soils. There are a number of problems associated with chamber measurements.
Emissions from soil are strongly influenced by pressure. With that in mind, scientists have suggested using some type of vent to keep the pressure inside a measurement chamber in equilibrium with the outside pressure. While such devices have worked under conditions where there was very little wind, these devices do not mimic the dynamic pressure component induced by wind outside the chamber. There is a need, therefore, for an improved vent design that will allow chamber pressures to stay in equilibrium with outside pressure in the face of changing static and dynamic components.
Further, any time gasses are moved from a sampling chamber to an instrument used to analyze gas concentrations, leaks can be (and often are) a problem. An apparatus and methodology for detecting leaks in such a system would be an important improvement, particularly as more complex systems are used involving multiplexing numerous chambers to a single analysis instrument thru some type of gas manifold.
Additionally, in any closed-transient measurement of gas exchange, volume must be known accurately. In most systems, it is unlikely that the volume is known any better than a few percent even when a chamber is placed on a level desktop. When a chamber is placed on an uneven soil surface and/or the surface has very large air filled pores, the problem is amplified. A technique to accurately estimate the kinetic volume of any given installation would be an improvement over the current state of the art.